I heard of a similar situation, there are times when trains almost drive themselves so the engineers don't need to pay much attention. The problem is when things go wrong and they need to act. Sometimes the engineers are so involved in other things that they fail to act.

That's one of the theories given for the cause of the 2008 Chatsworth train crash.

https://en.wikipedia.org/wiki/2008_Chatsworth_train_collisio...

It's still safer than not having it.

Arguably no, it's not. This is why Waymo stopped working on level 3 and switched to level 4/5 systems. It's also why most vehicle manufacturers up until now have only supplied ADAS features which provide backup to the human driver (lane departure warnings, emergency braking assistance etc.) rather than features which drive while using the human driver as backup.

There are a few coming out soon (SuperCruise, Pro Pilot) that will offer some degree of level 2/3 operation. It'll be very interesting to see how that goes liability-wise.

Not if it requires constant supervision, yet lulls the driver into a false sense of security such that they are predisposed to not provide that constant supervision.